I wonder if people will remember most writers take artistic license with the story and characters. Usually the viewer just accepts the story as fact, like Oliver Stones movie JFK. The story takes some liberties with Martha Mitchell. But, I wasn't there , so who can say what's true.
The production is very entertaining and portrayed the early seventies pretty well. I was a child, but I remember the seventies. Great acting by Julia Roberts and Sean Penn. He is completely unrecognizable in make up as John Mitchell. It's worth investing time to be watch.